The example given is as follows : we have 3 space ships(numbered from left to right) placed in space moving at velocity V in the same direction (they are moving to the right) , each one can send a pulse of light to the others and the others can determine time reached. so each of them is an observer , there is a fourth observer standing on earth(which is still according to his reference). Now we want to determine who appears to have slower time or faster according to fourth observer , so the following experiments are being done : observer 2 (the middle space ship) sends 2 light pulses to space ship 1(first spaceship) and 2(last ship on the right) according to the first 3 observers they all appear still to each other. so they will see light reaching from 2->1 and 2->3 , at the same time X , now observer 4 sees them all 3 moving with velocity V , when the even occurred according to him, the light reached to 1 first observer before reaching the third, but since 1st observer recorded a longer time , then time runs faster to him and the third observer will record a time shorter than what should be recorded from fourth perspective so time runs slower at 3rd. Conclusion from 1st experiment: Time runs slower at 3rd and faster at 1st. Now repeat experiment but sending the pulse from the 1st observer to the 2nd and 3rd. according to the first three everything is fine and running at the same speed , according to fourth observer, light will reach 2nd and third in longer time than that recorded by them meaning time is slower in 2nd and third. Conclusion from 2nd experiment: Time runs slower at 2nd and at 3rd. No contradictions so far Now here is the problem : Repeating the procedure by sending pulse this time from third observer to the 1st and 2nd, again for them everything appears to run at same time , but for fourth light will reach 2nd and first in shorter time than that recorded by 1st and 2nd , so that means that time runs faster at both 1st and 2nd. Conclusion from 3rd experiment: Time runs faster at 1st and at 2nd. The contradiction lies between experiment 2 and 3 where time cant be faster and slower at the same time for observer 4 regarding observer 2 . So any ideas ? Thanks and Best Regards, Omar Shaaban Ramzy.